Scientific Mastery Series Fly Lines feature advanced taper designs for improved shootability and casting in all weather conditions - setting the standard for fly lines around the world. Scientific Anglers Mastery GPX Fly Lines feature a general presentation taper, perfect for a wide range of fishing situations. GPX Fly Lines have a supple, low memory core which aids in line mending and are a half line size heavy to aid in casting today's fast action rods. Mastery GPX Fly Lines also feature a built-in streamlined loop for easy leader connections and Scientific Anglers AST Advanced Shooting Technology which helps line shoot farther, repel dirt and adds to the overall durability of the line. 3M's Dry Tip technology ensures the highest floating fly line tip sections on the market. This line is available in Chartreuse/Willow which features a Hi-Vis Chartreuse colored line with a Low-Impact Willow tip section. Mastery GPX is also available in the classic Optic Green color. This line is recommended for cold water use.